Printer hammer dampener



Nov. 4, 1952 w. E. EICKMAN PRINTER HAMMER DAMPENER Filed Nov. 18, 1949 FIG.3

mvsmon WILLIS E. EICKMAN HIS ATTORNEYS Patented Nov. 4, 1952 PRINTER HAIVHWER DAMPENER Willis E. Eickman, Dayton, Ohio, assignor to The National Cash Register Company, Dayton, Ohio, a corporation of Maryland Application November 18, 1949, SerialNo. 128,049

Claims. 1

This invention relates to improvements in printing hammer dampeners.

The principal object of the invention is to provide means to prevent spring-actuated printing hammers from rebounding after a printing stroke, to thereby avoid blurred impressions caused by an overprinting due to the reboundingof the printing hammer.

Another object of the invention is to provide a printing hammer dampener which can be applied to an existing hammer mechanism without the necessity of changing the construction of the hammer per se in any respect.

It is a specific object of the invention to provide a simpler mechanism, for preventing rebounding of a printing hammer, than those known in the prior art.

A specific object of the invention is to provide a dampening member adjacent a printing hammer, mounted on the same pivot as the hammer, and providing the dampening member with projections engageable with both sides of the printing hammer arm, the projections being spaced apart to provide room for relative movement between the hammer and the member.

With these and incidental objects in view, the invention includes certain novel features of construction and combinations of parts, a preferred form or embodiment of which is hereinafterdescribed with reference to the drawing which accompanies and forms a part of this specification.

In said drawing:

Fig. 1 is a side elevation of an embodiment of the invention shown applied to one type of printing mechanism.

Fig. 2 is a detail edge view of the weighted member associated with the printing hammer of Fig. 1.

Fig. 3 is a sectional view taken on line 3-3 of Fig. 1 and looking in the direction oi the arrows.

General description In order to prevent the rebound of the hammer, the present invention comprises a loosely mounted dampening member, pivoted on the same axis as the printinghammer and adjacent thereto, and said dampening member is provided with projections extending laterally therefrom and into the path of movement of the hammer. The projections are spaced far enough apart to permit relative movement of the hammer between the projections.

The dampening member may be constructed to receive a, plurality of weights in the form of plates to provide for varying its weight to accommodate the dampening member for varying requirements.

The projections on the dampening member are arranged to act as a counteracting means to prevent the hammer from being actuated a second time after an impression has been made on record material. When the hammer is operated by its spring to effect a sudden blow on the type carrier, one projection of the dampening member is engaged by the hammer, which carries the dampening member therewith, and, when the hammer is arrested by its contact with the type carrier, the momentum of the dampening member carries it forward. After the hammer strikes the type carriers it rebounds, and during such rebound movement the hammer meets the second projection of the dampening member, and the opposing forces of the two elements act to arrest the potential oscillatory movements of the hammer.

The weight of the dampening member varies with each installation and depends on a number of factors, such as the distance from the pivot point of the member to the center of the weight, the weight of the hammer, the strength of the springs for operating the hammer, friction, etc. To provide for the proper weight of the dampening member, Weights made up of a plurality of plates can be added to or removed from the dampening member according to the requirement of a particular installation.

Detailed description The mechanism illustrated in the drawing represents one form of printing mechanism to which the invention can be applied. In such a mechanism, a plurality of type carriers In, mounted on a stationary shaft II, are provided. These type carriers are adjusted to position any desired type characters on a printing line opposite a printing hammer platen [2, by any well-known means. The platen I2 is suitably mounted on the free end of a hammerv l3 pivotally mounted on a shaft I4. The hammer I3 has an arm I5, to which is secured one end of a, spring I6, the other end of which is secured to a stud H on a block I8, mounted on a hammer-operating lever I9. The lever I9 is pivoted on the shaft I4, adjacent the hammer I3. The spring I6 normally maintains a stud on the hammer I3 in contact with the upper end of the lever I9. 7

A spring 2I normally maintains the block I8 in contact with a stop 22 secured to a machine frame. A block 23, of rubber or any other suit.- able material, may be interposed between the block I8 and the stop 22 to act as a cushioning means to absorb the blow of thelever. I9 during machine operations, and to reduce,v eX $S ive noises resulting from such blows.

Connected to the lower end, of. thelever I9 is a link 24, the other end of which is connectedto an arm 25, pivoted on a shaft 26. The -arm:25,. 1

is secured to a cam follower 21, held in engagement with an operating cam 28 on the cam shaft 25 by the spring 2|.

Upon rotation of the cam 28 in thedirection indicated by the. arrow, the cam follower 21 is rocked counter-clockwise, thus moving the link 24 rightwardly, andthe spring 2 I .is.tensi oned At; the same, time, the lever I9,.. rocked. and the spring I6 causesthe studgZIl ofthehammer I3 to follow. the movementpf the. lever, I9. When the high point on the periphery of the cam. Z8 passes the end of the. cam follower 21, the spring 2.1 impels the lever. I9, and, through, the stud 20, impels the hammer I3 to cause the platen I2" to strike the. type carriers. After the. printing takes, place. the hammer I3 rebounds toward normal position, but, during thereturnof thehammer I3 toward normal position, the. stud 2|],v striking the spring-actuated. lever. I9, sometimes again member 30 (Figs. 1, 2, and 3)wis' loosely mounted on the shaft I4, adjacent the hammer I3; The

dampening member 30 is provided'withflanges- M and 32, formed to embrace the-hammer i3, and the flanges .are spaced 'apart topermit a limited free relative movement of the hammer I3- between the flanges. The'upper end of the dampening member 1 30 can be provided with one or more removable weights-33, by means of which the properweight can be attached thereto, for. the purpose presently described. The weights are located on'the dampening-member in-such; a position that gravity normally maintains the flange 3I in contact with the hammer I3. Shockand noise-absorbing material B l-maybeproVided on the inner walls of the fianges-3I and 32', if desired.

When the hammer I3 is impelled against the type in the manner described, the right ha'ndside (Fig. 1) of the hammer carries the dampening member 30 therewith unt-il'the hammer is stopped upon striking-the type carriers. The-mo mentum of the dampening member 30 is-sufficient at this time to carry it on after the hammerstrikes the type, carrier. Immediately thereafter, the hammer rebounds, and,. asthe, hammer returns toward its home positiomthe hammer is met by the flange 32 of the dampeningmember 30, which member is at this time approximately in the position in whichthe hammer is arrested in its home position. Both the hamm r I3 and the member 30 come to restsimultaneously due to the equalization of the force of each element acting on the other. The: rest period of the dampening member .30 is only momentary, since 4 gravity immediately restores the weighted member to its home position.

The opposing forces of the two elements act to dampen the potential oscillatory movements of the hammer, and, therefore, the hammer does not rebound to make a second impression, or to make what is known in the art as a shadow print.

..In dampening mechanisms known in the prior art, the means for obtaining the dampening effect were constructed at the time the printing mechanism was made and installed and. usually required special design of the parts. In applicants novel device, the dampener can be applied to any existing, printing hammer without redesigning thereof.

While the dampener shown herein is illustrated applied to a printing hammer, it is not limited in impelling the printing hammeragjainst the type carriers; a spring to restore the printing hammer to unoperated position afterbeing impelled a ainst t e yp rr ers;.. a pen ng mhammer, rigid projections, on the dampening member extending into the paths of movements of the impression hammer, said rigid projections being spaced apart, to enable the dampening member to moverelatively to thaprintingham mer when the printing hammer strikes the type carriers and rebounds therefron' and a weight.

on the. free end ofthedampening member to render the dampening membersufiicientl heavy to .arrest the hammer when the hammer engages one of the. rigid projections.- during the; said rebound movement of thehammer.

2. Thecombina'tionlof a shaft; an impression hammeripivotally mounted on said shaft;-type carriers; an-actuatorfor impelling; the. hammer against the type carriers; a dampening member pivotally mounted on..said shaft adjacentthe impression hammer; .two rigid projections, on the dampening member extending into. the paths of movement of theimpression hammer, one of said rigid projections. engaged: by the im pression hammer as the hammer is impelled in printing direction by the actuator, said rigid projections being spaced apart to. enable the.

' dampening member to move relatively to the printing hammer when the printing hammer strikes the type carriers and rebounds therefrom; and a weight mounted-onthe end of thedampening member remote fromthe shaft on which the dampening member ismounted to give the dampening member added momentum to cause the dampening member to move relatively to the-hammer after the hammer strikes the type carriers and rebounds, whereupon the hammer engagesthe other rigid projection to dampen the oscillations ofthe hammer.

3; The combination of a shaft, an impression hammer pivotally mounted on the shaft, type carriers, anactuating means to impelpthe impression hammer against the type carriers, a dampening member pivotally mounted on said shaft adjacent the impression hammer, a rigid projection on the dampening member projecting into the path of movement of the impression hammer when the impression hammer is impelled against the type carriers whereby the dampening member is moved therewith, a second rigid projection on the dampening member, said rigid projections being spaced apart an extent to enable the impression hammer to move relatively to the dampening member, said second projection being in the path of return movement of the impression hammer after an impression has been made by the hammer, said second projection being engaged by the hammer to dampen the oscillations of the hammer, and a weight comprising an inertia means on the free end of the dampening member.

4. The combination of a pivotally mounted impression hammer, type carriers, means to impel the impression hammer against the type carriers, a dampening member pivotally mounted beside the impression hammer, two rigid projections on the dampening member embracing the impression hammer, said rigid projections being spaced apart to permit relative movement between the impression hammer and the damp ening member, and a weight comprising an inertia means on the free end of the dampening member.

5. The combination of a pivotally mounted impression hammer movable from a home position into a printing position, type carriers, means to impel the impression hammer from the home position to printing position to take impressions from the type carriers and to return the impression hammer to home position, a dampening member pivotaily mounted beside the impression hammer, a pair of rigid projections on the dampening member embracing the impression hammer and spaced to permit relative movement between the hammer and the dampening member, and a weight in the free end of the impression hammer, said weight acting as an inertia means to arrest the impression hammer when returning to home position without setting up rebounding action in the hammer.

WILLIS E. EICKMAN.

I file of this patent:

UNITED STATES PATENTS Name Date Ellis Sept. 5, 1916 Number 

